In this type of engine starting apparatus, a crankshaft of the engine and the starter motor are connected via a one-way clutch. In the engine starting apparatus, if the engine runs in reverse rotation for some reasons, an excessive load is generated in the starter motor in some cases.
Thus, there is suggested an engine starting apparatus in which a reverse-rotation prevention clutch is mounted on an output shaft of the starter motor (e.g. refer to Japanese Patent Application Laying Open NO. 2003-83216). According to the apparatus disclosed by this application, by the action of a reverse-input cutoff clutch, a torque from the engine is not transmitted to the starter motor, regardless of the normal or reverse direction of the engine. Therefore, it is considered that even if the engine runs in the reverse rotation, the starter motor can be kept in a good condition.